Method for monitoring the properties of pharmaceutical articles

ABSTRACT

In a method for monitoring the properties of pharmaceutical articles ( 2 ), in particular capsules ( 2 ), in a machine ( 1 ) that makes the articles ( 2 ), the pharmaceutical articles ( 2 ) are fed in single file from a station ( 3 ) where the articles ( 2 ) are made to an article ( 2 ) outfeed portion ( 6 ) of the machine ( 1 ) along a defined feed path (P) passing through an inspection station ( 8 ). In the inspection station ( 8 ) each pharmaceutical article ( 2 ) passes through an electromagnetic field (E) created by microwave radiation.

TECHNICAL FIELD

[0001] The present invention relates to a method for monitoring theproperties of pharmaceutical articles.

[0002] In particular, the present invention can be advantageouslyapplied to capsule filling machines for making hard gelatin capsules forpharmaceutical use, of the type with lid and body, which the presentspecification expressly refers to but without restricting the scope ofthe invention, in order to monitor defined chemico-physical properties,such as, the weight of the capsules and/or the density and/or moisturein the doses of pharmaceutical material inside the capsules.

BACKGROUND ART

[0003] In prior art capsule filling machines of the rotary turret type,currently used for filling capsules with doses of pharmaceuticalmaterial in powder or particulate form, the capsule weight is monitoredin several ways, one of these being a statistical sampling methodwhereby defined quantities of sample capsules are taken at the outfeedend of the machine at defined time intervals and weighed on precisionbalances.

[0004] According to this method, which is manual and carried out outsidethe capsule filling machine, if a significant percentage of the sampledcapsules are found to be unsatisfactory in terms of weight or do notfall within specified ranges of values, the operator in charge oftesting operations must act directly on the capsule filling machine,modifying the dosing parameters of the unit that feeds and doses thepharmaceutical material.

[0005] In another method, known for example from European Patent EP886765 B1, all the capsules made by the capsule filling machine, or aspecified quantity of capsules, are fed into the hopper of a weighingapparatus located outside the capsule filing machine and connected tothe capsule filing machine by suitable conveying means. This weighingapparatus comprises a rotating suction drum which is mounted under thehopper and which feeds the capsules in single file to a series ofweighing heads followed by a conveyor chute with twin outfeed end.

[0006] The unit that controls the weighing apparatus receives andprocesses the signals from the weighing heads to derive the capsuleweights and accordingly activates a deflection plate on the twin-outfeedchute so that unsatisfactory capsules are channelled into the outfeedportion of the chute connected to the reject container, while thesatisfactory capsules are channelled into the other outfeed portion ofthe chute connected by suitable conveying means to a packaging machinedownstream, for example, a blister packer. Even this apparatus, however,does not eliminate the need for manual operations. Thus, in this casetoo, if a significant percentage of the capsules are found to beunsatisfactory in terms of weight or do not fall within specified rangesof values, the operator must act directly on the capsule filling machineto adjust the dosing parameters of the system that feeds and doses thepharmaceutical material.

[0007] Besides the inconvenience of having to operate manually, outsidethe capsule filling machine to adjust the pharmaceutical materialfeeding and dosing system when significant percentages of the capsulesare found to have an incorrect weight, there is also the disadvantagethat the above mentioned prior art methods do not permit the measurementof other chemico-physical properties of the capsules, for example, themoisture content of the pharmaceutical material inside the capsules,which have a considerable influence on the weight of the capsulesthemselves.

DISCLOSURE OF THE INVENTION

[0008] The aim of the present invention is therefore to provide a methodfor monitoring the properties of pharmaceutical articles that overcomesthe shortcomings and drawbacks of the prior art described above.

[0009] The invention accordingly provides a method for monitoring theproperties of pharmaceutical articles in a machine that makes thearticles, characterised in that the pharmaceutical articles are fed insingle file from a station where the articles are made to an outfeedstation of the articles themselves along a defined feed path passingthrough an inspection station; each pharmaceutical article passingthrough an electromagnetic field created by microwave radiation in theinspection station.

[0010] Preferably, crossing the electromagnetic field permitsmeasurement of the weight of the pharmaceutical article.

DESCRIPTION OF THE DRAWINGS

[0011] The invention will now be described with reference to theaccompanying drawings which illustrate a preferred, non-restrictingembodiment of a unit, implementing the method according to theinvention, for monitoring the properties of pharmaceutical articles, andin which:

[0012]FIG. 1 is a schematic plan view, partly in cross section and withsome parts cut away for clarity, of a preferred embodiment of the unitimplementing the method according to the invention; and

[0013]FIG. 2 is a schematic front view of a detail of the unit of FIG.1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0014] With reference to FIGS. 1 and 2, the numeral 1 denotes in itsentirety a machine for filling hard gelatin capsules of known type, eachhaving a lid C and a body F, with doses of pharmaceutical material M, inparticular pharmaceutical material M in powder or particulate form, suchas, for example, microtablets or pellets.

[0015] The capsule filling machine 1 is of well known type and basicallycomprises a station 3 for making the capsules 2, the station 3 in turncomprising a drum 4 that rotates, with alternating or continuous motion,in the direction indicated by the arrow K in FIG. 1, and being equippedon its periphery with a set of seats or bushes 5 for accommodating thecapsules 2 once closed and filled with the material M. The material M isfed to the drum 4 in a known manner, which is not illustrated, through acentral hopper 10 containing the material M which is dosed into thecapsules 2 through a dosing system SD of the type, disclosed forexample, in Italian Patent IT 1304779, with pistons that move insiderespective cylindrical dosing chambers.

[0016] In the bushes 5 of the drum 4, each capsule 2 is set in avertical position, that is to say, with longitudinal axis X (FIG. 2)positioned vertically and with the lid C at the top and the body Fbelow.

[0017] From the drum 4, each capsule 2 is removed in succession from arespective bush 5, by customary expulsion means, which are notillustrated, and fed in single file to an outfeed portion 6 of thecapsule filling machine 1 along a substantially straight feed path P bypneumatic conveying means which are of well known type and therefore notillustrated.

[0018] From the station 3 to the outfeed portion 6, the path P extendsthrough a guide 7 and through a capsule 2 inspection station 8, and,downstream of the inspection station 8, the path P is defined by achannel 50 that leads in a known manner which is not illustrated intothe infeed section of a packaging machine, for example a blister packer,also well known and not illustrated.

[0019] As shown in FIG. 2, the guide 7 is defined by a substantiallyhelical contact element 9 designed to gradually tip each capsule 2 by90°, so that it changes from an initially vertical orientation to ahorizontal orientation where its lid C and body F lie flat on the drum 4and where its longitudinal axis X is parallel to the horizontal planedefined by the drum 4 itself.

[0020] As illustrated in FIGS. 1 and 2, the inspection station 8comprises an operating unit 11 which in turn comprises a microwavesensor 12 defined by a structure 13 inside which there is created arotating electromagnetic field E of microwave radiation (that is to say,electromagnetic radiation with frequencies in the range from 10¹⁰ a 10¹²Hertz) to which each capsule 2 is subjected as it moves along the path Pand through the station 8.

[0021] More specifically, the microwave sensor 12 advantageously used isa sensor of known type, manufactured by the German company TEWSELEKTRONIC, with an electric circuit surrounded by a thin layer ofdielectric material, as described in U.S. Pat. No. 6,316,946 B2 and inU.S. patent application US 2001/0015649 A1, both in the name of ManfredTews.

[0022] Thus, as each capsule 2 passes through the inspection station 8,it crosses the electromagnetic field E generated by the microwave sensor12 which tests some of its chemico-physical properties such as thedensity p of the dose of material M with which each capsule 2 is filled,and the moisture content of the dose of the material M.

[0023] Since the volume of each capsule 2 is normally a known value andthe value of the density of the material M is measured by the microwavesensor 12, the real weight W of each capsule 2 can be easily calculatedfrom these values using the well known formula Weight W=(densityρ)×(Volume V).

[0024] The unit 11 also comprises a monitoring device 14 designed toreceive as input a signal relating to the measured value of the weightof each capsule 2 moving through the structure 13 and/or to the moisturecontent of the material M in the capsule 2, to compare this measuredvalue with a preset reference value, and to generate an output signalthat activates a device 15 for rejecting any capsules 2 that do notconform with the reference value.

[0025] As illustrated in FIG. 2, the rejection device 15 comprises anozzle 16 which is connected to a source S of air under pressure andwhich, on receiving a control signal from the monitoring device 14,issues a jet of air which diverts individual non-conforming capsules 2from the path P, causing them to be expelled and fed out through aconveyor channel 18 leading into a rejection container 17.

[0026] The monitoring device 14 is also connected to the machine 1system SD which doses the pharmaceutical material M so that, if asignificant average percentage of the checked capsules 2 are found to beunsatisfactory, the device 14 sends a feedback signal to the dosingsystem SD in order to automatically adjust the material M dosingparameters of the machine 1.

[0027] During experiments conducted on the system described above, itwas also found that the electromagnetic field E created by the microwaveradiation and crossed by the capsules 2 can also be used to detect thepresence in the material M of metal particles resulting from thetreatment which the material M undergoes before entering the machine 1.Thus, the monitoring device 14 might also be advantageously used toactivate the rejection device 15 to expel capsules 2 containing metalparticles mixed with the material M.

[0028] In the embodiment illustrated in FIG. 1, the channel 18 also hasa branch 19 with a deflector plate 20 which is controlled by the device14 and which can connect the channel 18 to the branch 19 which leadsinto a container 21.

[0029] Thus, when a statistical check on a defined quantity of samplecapsules 2 is required, the channel 18 is closed by the deflector plate20 and the capsules 2 expelled by the jet of air from the nozzle 16 arediverted into the branch 19 which channels them into the container 21.

[0030] Advantageously, the sample capsules 2 collected in the container21 can be weighed on analytical precision balances and the weights thusmeasured can be transferred to the memory medium of a personal computertogether with the weights measured by the unit 11, so that the two setsof values can be compared and checked for significant deviations.

[0031] Thus, the unit 11 and the microwave sensor 12 can be periodicallytested for working efficiency and, besides this, when deviations arefound in a significant average number of samples, the system SD fordosing the material M in the capsule filling machine 1 can be adjustedaccordingly.

[0032] To conclude, it is evident that the method as described above canbe optimally applied to automatically measure and check within themachine 1 the weights of all the capsules 2 made by the machine 1itself. Furthermore, the weights of only a specified quantity of samplecapsules 2 can also be checked.

1. A method for monitoring the properties of pharmaceutical articles (2) in a machine (1) that makes the articles (2), characterised in that the pharmaceutical articles (2) are fed in single file from a station (3) where the articles (2) are made to an outfeed portion (6) of the machine (1) along a defined feed path (P) passing through an inspection station (8); each pharmaceutical article (2), as it travels through the inspection station (8), passing through an electromagnetic field (E) created by microwave radiation.
 2. The method according to claim 1, characterised in that the crossing of the electromagnetic field (E) permits measurement of the weight (W) of the article (2).
 3. The method according to claim 1, characterised in that the articles (2) comprise hard gelatin capsules (2) of the type with lid and body (CF) containing doses of pharmaceutical material (M) in powder or particulate form, and in that the machine (1) comprises a capsule filling machine (1) that makes the pharmaceutical capsules (2); the crossing of the electromagnetic field (E) permitting calculation of the weight (W) of the capsules (2) through measurement of density (p) of the pharmaceutical material (M) inside each capsule (2).
 4. The method according to claim 3, characterised in that the crossing of the electromagnetic field (E) by the capsules (2) also permits measurement of the moisture content of the dose of pharmaceutical material (M) inside each capsule (2).
 5. The method according to claim 3 or 4, characterised in that the crossing of the electromagnetic field (E) by the capsules (2) also permits detection of any metal particles in the pharmaceutical material (M).
 6. The method according to claim 4, characterised in that the electromagnetic field (E) of microwave radiation is produced by an operating unit (11) which is located inside the inspection station (8) of the machine (1) and which comprises a microwave sensor (12) and a monitoring device (14); the monitoring device (14) being designed to receive as input a signal relating to the measured value of the properties of the articles (2), to compare this measured value with a preset reference value, and to send an output signal that activates a device (15) for rejecting the articles (2) that do not conform with the reference value.
 7. The method according to claim 6, characterised in that the monitoring device (14) is connected to a unit (10, SD) for feeding and dosing the pharmaceutical material (M) in the capsule filling machine (1).
 8. The method according to claim 6 or 7, characterised in that the rejection device (15) is located at the outfeed portion (6) on the path (P) and comprises deflecting means (16; S) for diverting non-conforming articles (2) from the path (P), causing the non-conforming articles to be expelled into a rejection container (17).
 9. The method according to claim 8, characterised in that, in the machine (1), the articles (2) are fed from the production station (3) to the outfeed portion (6) along a feed path (P) that passes through the inspection station (8) and is substantially straight.
 10. The method according to claim 8, characterised in that the articles (2) are overturned as they move along the straight path (P) upstream of the inspection station (8). 